Marijuana refers to the dried flowers, leaves, stems, and seeds of the Cannabis sativa or Cannabis indica plant, containing the psychoactive compound delta-9-tetrahydrocannabinol (THC). Understanding the effects of chronic marijuana use requires focusing on this sustained, high-frequency pattern, which alters the body’s natural systems and can lead to significant changes in daily life. This persistent use is distinct from occasional use because it often results in a cycle of dependence and tolerance, where the individual’s system adapts to the constant presence of THC.
Establishing the Criteria for Chronic Use
Chronic or heavy marijuana use is typically defined by a pattern of daily or near-daily consumption maintained over an extended period. This frequent use can lead to the development of a clinical condition known as Cannabis Use Disorder (CUD), a diagnosis recognized in the primary manual for mental health professionals. The diagnosis focuses on a problematic pattern of use that causes significant distress or impairment.
A diagnosis of CUD is based on meeting a specific number of criteria within a 12-month period, which reflect impaired control over use and continued use despite negative consequences. These criteria include a strong desire or urge to use the substance, known as craving, and a development of tolerance, meaning a need for increasing amounts to achieve the desired effect. The disorder also reflects a pattern where a person spends a substantial amount of time obtaining, using, or recovering from the effects of the substance.
The classification of CUD, ranging from mild to severe, is determined by the number of symptoms a person experiences. The central concept is that the substance use takes precedence over other aspects of life, such as fulfilling major obligations at work, school, or home. This persistent pattern of use despite knowledge of having a recurrent physical or psychological problem further defines the chronic nature of the condition.
Physical and Mental Health Consequences
Chronic marijuana use affects the respiratory and cardiovascular systems.
Physical Health Effects
For individuals who smoke the substance, long-term inhalation of marijuana smoke is associated with respiratory issues, including symptoms of chronic bronchitis such as persistent coughing and increased phlegm production. The smoke contains irritants and toxins found in tobacco smoke, which can damage the lung tissues and airways.
The cardiovascular system is affected by chronic use, as THC causes an immediate increase in heart rate and blood pressure shortly after consumption. This repeated stress on the heart may increase the risk of cardiovascular events, though the relationship requires further study. Another physical condition linked to chronic, high-dose use is cannabinoid hyperemesis syndrome, which causes recurrent, severe cycles of nausea, vomiting, and abdominal pain.
Cognitive and Mental Health Effects
The impact on cognitive function is significant, especially for those who begin using during adolescence when the brain is still developing. Chronic exposure to THC can impair cognitive functions like attention, memory, and executive functions, including planning and decision-making. This cognitive impairment can persist beyond periods of intoxication, affecting performance in school or at work.
Chronic marijuana use may be associated with an increased risk of developing or worsening conditions like anxiety and depression. For individuals who are predisposed, heavy use, particularly of high-potency products, has a statistical association with the development of psychosis or schizophrenia spectrum disorders. While cannabis does not cause these conditions, it can hasten their onset or exacerbate symptoms in vulnerable individuals.
Navigating Cannabis Withdrawal
When a person stops or significantly reduces their intake after a period of heavy, chronic use, they may experience cannabis withdrawal syndrome. Symptoms typically begin within one to two days after the last use and usually peak in severity between days two and six.
Psychological symptoms include:
- Heightened irritability, anger, and restlessness.
- Feelings of nervousness or anxiety.
- Depressed mood and a general sense of unease.
Physical manifestations frequently involve:
- Significant sleep disturbances, such as insomnia and vivid dreams.
- Decreased appetite and minor weight loss.
- Headaches, sweating, and tremors.
While acute physical symptoms usually resolve within three weeks, some psychological symptoms, particularly sleep problems and cravings, can occasionally linger for a month or more.
Pathways for Addressing Heavy Marijuana Use
Individuals seeking to reduce or stop heavy marijuana use have access to several evidence-based interventions that focus primarily on behavioral change. Since there are currently no medications approved specifically for the treatment of CUD, behavioral therapies aim to equip individuals with the skills necessary to manage cravings and maintain abstinence.
Cognitive Behavioral Therapy (CBT)
CBT helps individuals recognize the thoughts, feelings, and situations that trigger their substance use. By identifying these patterns, patients develop effective coping mechanisms and problem-solving strategies to navigate high-risk situations without resorting to cannabis. This therapy focuses on modifying maladaptive behaviors and thought processes.
Motivational Enhancement Therapy (MET)
MET helps individuals resolve their ambivalence about changing their use patterns. It works to enhance the person’s internal motivation by exploring their personal reasons for wanting to reduce or stop using cannabis. This therapy is often beneficial early in the treatment process.
While no pharmacological treatments are explicitly approved, some medications are used to manage specific withdrawal symptoms or co-occurring mental health conditions. Research is ongoing into compounds like N-acetylcysteine and gabapentin, which have shown limited promise in reducing cannabis use or withdrawal symptoms in clinical studies. Ultimately, a combination of behavioral therapy, often supported by contingency management that uses incentives to reinforce abstinence, represents the current standard of care.